Chronic metabolic diseases can begin in just 14 days of inactivity

Just 2 weeks of increased sedentary behavior can reduce muscle mass and cardio-respiratory fitness in healthy young individuals, which can increase the probability of developing chronic metabolic disorders and premature death, according to data presented at the European Congress on Obesity.

Because the consequences of reducing habitual physical activity remains unknown, Dan Cuthbertson, PhD, from the Institute of Ageing and Chronic Disease at the University of Liverpool, England, and colleagues examined the risk factors for chronic disease after 14 days of physical inactivity.

The study included 28 healthy, physically active individuals with a normal BMI and a mean age of 25 years. Each participant wore a SenseWear armband to measure physical activity. To ensure no changes in food intake occurred throughout the intervention, each participant completed a dietary journal. Participants received comprehensive health checks of fat and muscle mass, mitochondrial function and physical fitness at the start of the study and after a 14-day step reduction protocol, which cut their activity by more than 80% to around 1,500 steps per day.

The results showed that the step reduction protocol decreased moderate-to-vigorous activity from a daily average of 161 minutes to 36 minutes while daily sedentary time increased by an average of 129 minutes at the same time. Following the 2 week-period of inactivity, researchers observed loss of skeletal muscle mass and increased total body fat that tended to accumulate centrally, which is a major risk factor for developing chronic disease. Participants’ cardio-respiratory fitness levels also weakened significantly, resulting in the inability to run at their previous duration and intensity. The substantial loss in muscle mass included a reduction in both whole body lean mass and leg lean mass, with an average loss of 0.36 kg and 0.21 kg, respectively.

“Just 14 days of increased sedentary behavior resulted in small but significant reductions in fitness that were accompanied by reductions in muscle mass and increases in body fat. Such changes can lead to chronic metabolic disease and premature death,” Cuthbertson said in the press release. “The results emphasize the importance of remaining physically active, and highlight the dangerous consequences of continuous sedentary behavior. Our day-to-day physical activity is key to abstaining from disease and health complications.” – by Savannah Demko

References: Cuthbertson D, et al. Abstracts T2P143 and T2P164. Presented at: European Congress on Obesity; May 17-20, 2017; Porto, Portugal.

Disclosures: Cuthbertson reports no relevant financial disclosures.